Electro thermal relay



1960 w. c. BROEKHUYSEN 2,948,788

EILECTRO THERMAL RELAY Filed Jan. 28, 1957 4 Sheets-Sheet l 1 I 58 4 6 I F a, 76 i i 76 v 1 1 I a I 1 l l 78 i I 75 20 & J 78 Aug. 9, 1960 w. c. BROEKHUYSEN 2,948,788

ELECTRO THERMAL RELAY Filed Jan. 28, 1957 4 Sheets-Sheet 3 lfig 7 m 2 228 g- 1960 w. c. BROEKHUYSEN 2,948,788

ELECTRO THERMAL RELAY Filed Jan. 28; 1957 4 Sheets-Sheet 4 United States Patent O ELECTRO THERMAL RELAY William C. Broekhuysen, Brooklyn, N.Y., assignor to 'G-V Controls Inc., East Orange, N.J., a corporation of New Jersey Filed Jan. 28, 1957, Ser. No. 636,628

34 Claims. (Cl. 200-122) This invention relates to improvement in electro-t-hermally actuated relays, and more particularly to relays of this type which are simple and rugged in construction, flexible and economical to manufacture, which will meet all normal conditions and which will satisfy a very wide range of requirements of use in industry and commerce.

Relays constructed in accordance with the invention can be produced in quantity and be available for wide use at relatively low cost. Although in the prior art relays provided with elongated heat-expansible controlling members are known, nevertheless because of their rather intricate and specialized design, they have usually covered only a limited range of requirements in any one design and have not been readily adaptable for use in industry generally.

Relays embodying the invention are enclosed in a dusttight casing which protects them against anything but abnormal conditions of use. They can be adjusted simply and readily in order to adapt them for a wide range of operating conditions, and they are also compensated for ambient temperature changes. Their design permits manufacture of the structure in two parts, one of which is common to all structures while the other can be produced in a number of modifications, all based on the same principle of thermal elongation but varied in detail so as to provide a heretofore unknown degree of adaptability to a wide range of requirements.

It is an object of the invention to provide a novel electro-therrnally actuated relay of the type having an elongated heat-expansible controlling member, which is operative in response to the passage of a current therethrough to sheet the desired relative movement of the contacts thereof in making or breaking or controlling the circuit of which it forms a component.

It is a further object of the invention to provide a novel electro-thcrmally actuated relay which is simple, economical to produce, and rugged in construction, and which is reliable under all normal industrial and commercial conditions of use to which it is subjected.

The invention further consists of the provision of a novel electro-thermally actuated relay having an elongated heat expansible controlling member, which relay is simple and rugged, economical and flexible in manufact-ure in quantity, and one which has good compensation over a wide range of ambient temperature changes, thus making it available to commerce and industrial uses under all normal operating conditions.

With these and other objects not specifically mentioned in view, the invention consists in certain combinations and constructions. which will be described fully hereinafter, and then set forth in the claims hereunto appended.

In the accompanying drawings, which form a part of this specification, and in which like characters of reference indicate the same or like parts:

Figure 1 is a side elevation in cross-section of a preferred form of construction of electro-thermal relay provided with normally open contacts constructed inaccord- 'ance with the invention.

2,948,788 Patented Aug. 9, 1960 "ice Figure 2 is a view taken on line 22 in Figure 1.

Figure 3 is a view taken on line 33 in Figure 1, with the casing omitted.

Figure 4 is a side elevation in cross-section of a modified form of the invention with normally closed contacts.

Figure 5 is -a view taken on line 55 in Figure 4.

Figure 6 is a view taken on line 6-6 in Figure 4 with the casing omitted.

Figure 7 is a front view of a part of a heating or controlling member wherein the wires are electrically in series and mechanically in parallel.

Figure 8 is a side view of the heater shown in Figure 7.

Figure 9 is a sectional view taken on line 9-9 in Figure 8. L

Figure 10 is a sectional view taken on line 10-10 in Figure 8.

Figure 11 is a front view of a completed heater ready for assembly in a relay.

Figure 12 is a side view of the heater shown in Figure 11.

Figures 13, 14 and 15 are sectional views taken on lines 13--13, 14-14 and 15-15, respectively, in Figure 12.

Figure 16 is a view taken on line 1616 in Figure 2.

Figure 17 is a side elevation of a further modified form of the invention provided with a set of normally open and a set of normally closed contacts.

Figure 18 is a schematic diagram showing a typical circuit in which the relay of Figure 17 may be connected for operation.

In the preferred embodiment of the invention selected for purposes of illustration, shown in Figures 1, 2, 3 and 16, the electro-thermally operated relay designated generally v10 is provided with a molded base 12 similar to those used in conventional octal radio tubes. Base 12 is provided with an integral molded keyed pilot 14. Base 12 has eight holes in which are inserted hollow pins 1-8 each provided with a head or shoulder 16 with which it rests against the bottom of base 12. Two L-shaped brackets 18 and 20 are attached to base 12 by staked pins 5 and 6, and 1 and 8, respectively. Contact bracket 22 which supports fixed contact 24 is attached to base 12 by staked pins 4 and 7. Bent wires 26 and 28 are secured in hollow pins 2, and 3, respectively, which are staked directly to base 12. Pin 1 is insulated from bracket 20 by insulating shoulder bushing 30, but is electrically connected to a grounding strap 32 having one end secured to the top of staked pin 1.

Referring to Figures 1 and 2, it will be seen that base 12 has a circular shoulder 34- and a rim 36 which supports the flared bottom of shell or casing 38. Rim 36 is cut by a groove 41) at four equally spaced points. These grooves are undercut and extend as slanted recesses 42 into shoulder 34, as shown in Figure 2. The bottom flared edge of casing 33 is crimped into recesses 42, thereby firmly attaching casing 38 to base 12. As shown in Figure 2, the free end of grounding strap 32 extends into one of the grooves 40, and is firmly gripped by the crimped edge of casing 38 against base 12 where it forms an electrical connection from casing 38 to pin 1, through which casing 38 is connected to ground when this is desired. 7

Pin 5 provides the electrical connection to bracket 18, and pin 7 forms an electrical connection to bracket 22. If desired, pins 4, 6, and 8 may be replaced by hollow rivets. This eliminates the possibility of shorts in cases where unused points in the socket into which relay 10 is plugged are used as tie points. The lower tips of all pins are sealed off in any suitable conventional man- 3 ner, as by dipping in solder, which also anchors wires 26 and 28 in pins 2 and 3.

The assembled relay movement is mounted on an elongated channel-shaped frame 43 which carries at its top (see Figure 1) a U-shaped bracket 44. One end of an electrically heatable elongated longitudinally expansible controlling member 46 is attached, as by welding, to bracket 44 at a point designated C by means of a flat resilient spring 48. An elongated channel-shaped compensating member 50 is flexibly connected to frame 43 ata point designated D preferably a short distance from point C by an extension 52 forming an integral part of compensating member 50. A U-shaped bracket 54 is rigidly secured to the free end of compensating member 50. The other end of controlling member 46 is flexibly attached to bracket 54 at a point designated E by a flat resilient spring 56.

The construction of controlling member 46 may be the same as that shown and described in my Patent 2,700,- 084. In general, it comprises an elongated open seam tubular metal shell 58, substantially rectangular in crosssection. See Figure 16. In the center of this shell is a heater consisting of a thin strip of insulating material, such as mica 60, on which is wound a suitable number of turns of fine resistance wire 62, sandwiched in between two layers 64 and 66 of suitable insulating material, such as mica. The remaining space within tubular shell 58 is filled up by strips of metal 68 to increase the thermal capacity of controlling member 46. The entire assembly is tightly compressed within shell 58 to form a solid unit. Tubular shell 58 and strips 68 preferably are made of a metal with a relatively high coeflicient of thermal expansion. It is preferred to use a corrosion resistant material, such as stainless steel.

A forked tapped bracket 70 is attached rigidly to the free end of compensating member 50 adjacent bracket 54. A short adjusting screw 72 is inserted in bracket 70 and is gripped between the two tapped arms or sides of the fork so that it can be turned to eifect the desired adjustment without becoming loose. Adjusting screw 72 bears against moving contact spring 74, which is. attached at one end to frame 43 and carries a double sided contact 76 at its free end. Leads 78 of heatable controlling member 46 are connected to wires 26 and 28 in pins 2 and 3. From what has been described hereinabove, it is apparent that adjustment of screw 72 changes the gap between contacts 76 and 24 and thereby changes the time that elapses between the application of an electrical potential to pins 2 and 3, and the closing of the contacts.

Referring to Figure 1, it will be seen that points C, D and E from a triangle. Controlling member 46 and compensating member 50 form the long sides of the triangle, and the short distance CD is the base. When controlling member 46 is heated by applying an electrical potential to pins 2 and 3, it will expand longitudinally and move point E towards frame 43 and contact 76 towards contact 24. If distance CD is short compared to distances CE and DE, the longitudinal expansion of controlling member 46 will produce a substantially greater movement of point B and screw 72. Because adjusting screw 72 bears against an intermediate point on spring 74, the movement of contact 76 will be greater than that of screw 72. Further expansion of controlling member 46 after contact 76 engages contact 24 will produce flexing of spring 74 and a slight rolling action of contact 76 relative to contact 24 which helps to insure and main tain a good connection between the contacts.

U-shaped bracket 54 serves to reduce the thermal coupling between controlling member 46 and compensating member 50 because it increases the spacing between these two members without reducing the ratio of multiplication. As shown in Figure 1, because of its channel form and manner of mounting, compensating memb i. 0 par- '4 tially surrounds frame 43, and thereby provides a more intimate coupling between these two channel-shaped members. These two factors combine to produce a substantial difference in temperature between compensating member 50 and controlling member 46 for a moderate energy input into the heater of controlling member 46.

If frame 43 or at least the top section thereof, controlling member 46 and compensating member 50 are made of the same material, such as stainless steel, or of material having the same temperature coefficient of expansion, a change in ambient temperature will produce no relative movement between the contacts.

Contact 76 is connected by spring 74 to frame 43, which is attached to pin 5. Thus when contacts 24 and 76 engage, current will fiow from pin 5 through bracket 18, frame 43, spring 74 and contact 76 to contact 24, bracket 22 and pin 7. This current cannot cause any heating of controlling member 46 or compensating member 50, or produce any movement of point B, because it does not flow through these members.

Relay 10 shown in Figures 1 and 2 is one having normally open contacts. Since contact 76 is a double sided contact, relay 10 can be converted into a normally closed contacts type by repositioning contact 24 on the rear of its support arm on bracket 22, and changing the position of spring 74 so that the contact face shown continuously out of engagement with contact 24 in Figure 1, normally bears against contact 24 as shown in Figure 4. The operation of the relay remains the same except for the contacts action.

Adjustment of screw 72 in Figure 1 will change the gap between contacts 24 and 76 and thereby change the time that will elapse between the application of an electrical potential to pins 2 and 3 and the closing of the contacts. If the contacts are normally closed, there will be an initial gap between the tip of screw 72, or 172, and spring 74 or 174, as shown in Figure 4. Adjustment of the screw will then change that gap and thereby change the time-delay between the application of an electrical potential to pins 2 and 3 and the opening of the contacts.

It is preferred to make the necessary adjustments of screw 72 in relay 10 and in relay 100 and 3300 described hereinafter at the factory. However, if adjustments are required in the field, they can be made by merely inserting the operative end of a screw driver through openings in the casings, such as opening 80 in casing 38, engaging the slitted end of screw 72 and turning the screw driver in one direction or the other to make the desired adjustment. In order to insure against the access of dust and foreign material into casing 38, a plug 39 of suitable material, such as rubber is seated in opening 80 where it can be removed manually when adjustment is required.

The above-described time-relays are further dependent on the thermal capacity of the controlling member, the amount of energy put into the heater and the rate of heat loss to the surrounding atmosphere and to other parts of the relay. The thermal capacity of the controlling member 46 may be varied by decreasing or increasing the number and thickness of the filler strips 68 and the thickness of shell 58.

The embodiment of the invention shown in Figures 4, 5 and 6 shows a construction of the controlling member for obtaining shorter time delays than can be obtained with the construction of Figures 1, 2, 3 and 16. In Figures 4, 5 and 6, base 12 is the same as base 12 in Figures l-3, and is also provided with eight holes in which are inserted hollow pins 1-8, as described above. Two L-shaped brackets 18 and 20 are attached to base 12 shown in Figures 4-6 in the same manner as in the relay shown in Figures 1-3. Bent wires 26 and 28 are secured to hollow pins 2 and 3, respectively, which are staked directly to base 12. Pin 1 is insulated from bracket 20 by insulating shoulder bushing 30, but is electrically connected to grounding strap 32 having one end attached to the top of staked pin 1. Casing 38 is mounted on base 12 in the same manner as casing 38 in the relay shown in Figures 1 and 2, and the operative connections of pin -5 are also the same. Similarly pins 4, 6 and 8 can be replaced by hollow rivets for the purposes described hereinabove. Base 12 is also provided with a contact bracket 122 having an arm 123 attached thereto on which is mounted fixed contact 124. Bracket 122 is attached to base '12 by staked pins 4 and 7.v

The movement of relay 100 is supported on an elongated channel-shaped frame, designated generally 143, at the top of which is mounted a U-shaped bracket 144. As in the case of relay 10, frame 143 is positioned substantially at right angles to the plane of base 12.

In relay 100, the heatable expansible controlling member 146 consists of a flat metal ribbon 147 formed from a suitable metal, such as stainless steel. The central portion of ribbon 147 is surrounded by a suitable number of turns of fine resistance wire 149 which is insulated from ribbon 147 by two fiat pieces 151 of insulating material, as for example mica. The free ends of metal ribbon 147 extend beyond the mica pieces 151.

The upper free end 148 of metal ribbon 147 is attached, as by welding, to bracket 144 at a point designated C. Elongated channel-shaped compensating member 150 is flexibly connected at its upper end to frame 143 at a point designated D, by an extension 152 form- "ing an integral part of member 150, a short distance from point C. The lower free end 156 of controlling member metal ribbon 147 is attached at a point designated E to the base of U-shaped bracket 154 rigidly secured to the free end of compensating member 150.

A forked tapped bracket 170 is rigidly attached to the free end of compensating member 150 adjacent bracket 154. Gripped between the two arms or sides of bracket 170, and turnably mounted therein is an adjusting screw 172 which can be turned to effect the desired adjustment without becoming loose. Leads 178 and 179 are connected to base wires 26 and 28, respectively, in pins 2 and 3.

Since metal ribbon 147 is flexible, it does not possess sufficient rigidity to effect the desired operation of relay 1100, and for that reason it must be maintained under tension in order to produce movement of screw 172 against the pressure of spring 174 when ribbon 147 expends due to being heated. The necessary tension is obtained by a coil spring 180 positioned between frame 143 and the base of a U-shaped bracket 182 attached to compensating member 150, preferably adjacent its free end. Spring 180 is maintained in operative position by providing dimples 181, and 184 in frame 143, and bracket 182, respectively, on which the ends of the spring are seated. See Figure 4.

In order to secure against access of dust and foreign material the opening 141 provided in casing 138 to allow ready insertion of a screwdriver for adjusting screw 172 is normally closed with a manually removable plug 139,

such as rubber. As in the case of relay 10, however, it is usually preferred to make all adjustments at the factory, and in accordance with the requirements of the customer.

Referring to Figure 4, adjusting screw 172 is initially spaced from movable contact spring 174 having one end attached to frame 143. The free end of spring 174 carries a double-sided contact 176 adapted to be moved relative to fixed contact 124. In the relay 100' shown, contacts 124 and 176 are normally engaged. Expansion of member 146 will cause screw 172 to engage spring 174 and separate contact 17 6 from contact 124. It is obvious however, that by reversing the positions of contacts 124 and 176 in the manner shown in Figure 1, relay 100 can readily be converted into a normally open contacts type.

The relationship of points C, D and E is essentially the same as that of points (3, D and E in relay 100. The operation is also the same, except that in relay 100, when 6 an electrical potential heats controlling member 146 and causes it to elongate, contact 176 is moved away from contact 124 and breaks the circuit of which the relay forms a component part. The time-delay obtainable with controlling member 146 may further be varied by in creasing or decreasing the thickness of metal strip 147.

If a still shorter time-delay range is required, a heatable controlling member of the type shown in Figures 7 to 15 inclusive can be used in place of controlling member 146 in relay 100. In the relay controlling member disclosed in these figures the expanding member consists of a grid of resistance wires which are heated directly by passing a current through them. The strands of resistance wire forming the grid are electrically in series and mechanically in parallel. Because of the construction of the grid, if a strand of the wire should break, the grid as a whole will not collapse. The controlling member, designated generally 2%, shown in Figures 7l5 is substantially the same in construction as that disclosed in my co-pending application S.N. 322,905, filed November .28, 1952, for Electrical Control Devices, now Patent 2,809,253, granted October 8, 1957, and therefore, only such description will be given herein as is necessary to an understanding of the manner in which it is made and its operation will be set forth herein.

Heated timing member 200 consists of a grid of fine resistance wire originally wound on a thin fiat frame 224, partially designated in broken lines in Figures 7 and 11, of suitable shape and thickness and made of a suitable insulating material with high mechanical strength and rigidity, such as mica. Frame 224 is substantially rectangular in shape and is provided with an extention 223 at each end. Frame 224 is also provided with a central substantially rectangular opening 220. Wire 222 is wound around the full length of frame 224 and back and forth over end-extensions 223 and between ears 221 formed in end-extensions 223 as many times as required for the desired resistance. The two ends of the winding are secured in notches 225, as shown in Figures 7 and 11.

Each extension 223 is provided with two spaced slots 226. The frame is supported at top and bottom by two flat staples 228 and 230, preferably formed of stainless steel, which extend through slots 226. Staple 230 is connected to a flat short flexible spring 240 by means of which it can be secured to bracket 154 of relay 100. Staple 228 is connected to a similar fiat short flexible spring 241, which is in turn secured to bracket 244 of relay 100.

Figures 7-10 illustrate one type of grid structure in which the wires are electrically in series and mechanically in parallel. In the grid shown in these figures, two short pieces of mica 234 are supported on each of the staples 228 and 230, one piece on each side of wires 222, for electrical insulation. In assembling grid 200 in a relay movement spring 240 and bracket 144 are attached to their respective supports and then side pieces 219 of frame 224 are broken or cut off. This leaves the grid 200 supported under tension and in operative position in a relay 100.

The grid structure shown in Figures 11-15 is the same as that shown in Figures 7-10 with the addition of two longer side pieces of mica 232 held in contact with the wire grid by staples 228 and 230 and a central staple 236. The manner of mounting and use in relay 100 is the same as described directly above. The effect of these strips of mica in contact with the wire strands is an apparent increase in the thermal capacity of the strands, without changing their electrical resistance.

The arrangement of the resistance wire in a grid 200 in which the strands of wire are electrically in series and mechanically in parallel, and the manner in which the staples 228 and 238 coact with the end-extensions 223 and with mica pieces 232 and 234 to clamp the ends of the strands, has the result that when the staples 228 and 230 are bent into gripping position, even if one or more strands of wire should break, the grid structure retains its mechanical integrity.

1 In' the first embodiment of my invention, as well as in each of the modifications described above, each of the types of heatable controlling members can be made with more than one time-constant. In addition, the heating element in each of these types can be wound for many diiferent voltages. Thus a wide variety of combinations of time-constants and heater voltages is possible, without any change in the basic design of the relay. Many additional modifications are possible to adapt the basic design to special requirements. Figures 17 and 18 illustrate one form of my invention which includes a make-before-break contact construction. Referring to Figure 17, the base of the relay is designated 312; the casing is not shown. Base 312 is generally the same in construction as base 12 and further description thereof is deemed unnecessary. L-shaped bracket 373 is mounted on and secured to base 312 by staked pin 7. one leg of an inverted V spring 378 is fixed to the vertical arm of bracket 373; the other leg of spring 378 carries two spaced contacts 380 and 38 2. Another L-shaped bracket 384 is held fixed to base 312 by pin 3 which supports wire 328 to which one lead 366 of heatable controlling member 346 is attached. Controlling member 346 may be the same in construction as member 46, member 146, or member 200 described hereinabove. Contact 386 is carried by the vertical arm of bracket 384. Contact 382 normally is held in engagement with contact 386 by the pressure of spring 378.

The relay shown in Figure 17, designated generally 300, includes a supporting frame 343, a compensating member 350, tapped forked bracket 37 carried by compensating member 350, adjusting and operating screw 372 mounted in bracket 370, and contact supporting spring 375 which correspond in construction and operation to similar members described hereinabove and illustrated in relays and 100.

In the operation of relay 300, when heater or con trolling member 346 is energized by the passage of an electric potential therethrough, contact 376 will move towards and engage contact 380. Further expansion of controlling member 346 will effect a separation of contacts 382 and 386. If the heater of controlling member 346 is connected in series with these contacts, as shown diagrammatically in Figure 18, this action can be used to advantage. As soon as contacts 382 and 386 disengage, member 346 starts to cool, thereby causing the re-engagement of contacts 382 and 386. This cycle will be repeated indefinitely so long as power is applied to pins 2 and 7, and member 346 will be maintained at a substantially constant temperature just sufiicient to keep contacts 376 and 380 engaged. However, any interruption of power will cause an almost immediate opening of contacts 376 and 380, so that, upon re-application of power to pins 2 and 7, at least part of the original delay in the closing of contacts 376 and 380 will have been recovered. It will be apparent, therefore, that relay 300 provides a thermal time-delay relay in which the recycling time is low compared to the normal time delay. Resistance 387 and capacitor 388 are connected in multiple between pins 3 and 7, shunting contacts 382 and 386 for suppression of arcing at these contacts.

The circuit described above is particularly useful in applications which require a time-delay proportional to the duration of a power interruption, for example, for protecting the cathodes of thyratrons and similar tubes.

The movable or second contact, if desired, can be mounted directly on the free end of the set screw which is carried by the joined ends of the controlling and compensating members. For example, in the embodiments of the invention illustrated herein, movable contact 376 as shown diagrammatically in Figure 18, may be c0nsidered to be mounted on the end of set screw 372. When controlling member 346 elongates due to its heater being energized contact 376 will move into engagement with contact 380 in response to the conjoint movement of controlling member 346 and compensating member 350.

It is noteworthy that the invention provides'a novel relay structure, capable of adaptation to many industrial and commercial uses, wherein the basic structure is separable into two parts for accomplishing these advantages. The described separation of the base and movement which results in great interchangeability permits quantity manufacture of the base ,in only twotypes: normally open and normally closed contacts types. The movement can be further sub-divided into two sub-assemblies, (A) frame plus compensating member, and (B) controlling member. In (A) these are two types, (1) with. coil spring and bracket, and (2) without coil spring and bracket. The controlling member is made to suit the requirements of the particular application.

What I claim is:

1. In an electro-thermally actuated relay, in combination, a base, a first contact mounted on said base, a relay movement comprising a frame mounted on said base, an elongated electrically heated expansible controlling member, means mounting one end of said controlling member on said frame, an elongated compensating member, means mounting one end of said compensating member on said frame and disposing said compensating member in spaced relationship with said controlling member, connecting means joining the free end of said controlling member and the free end of said compensating member, a second contact, support means for said second contact, and means carried by said joined ends-of said controlling member and said compensating member and the conjoint lateral movement of the connected ends of said controlling member and said compensating member and operative in response to the expansion of said controlling member when said controlling member is heated for effecting relative movement between said second and said first contact.

2. In an electro-thermally actuated relay, in combination, a base, a fixed contact mounted on said base, a relay movement comprising a frame mounted on said base, an elongated electrically heated expansible controlling member carried by said frame, an elongated compensating member also carried by said fname and disposed in spaced substantially parallel relationship with said controlling member, connecting means joining one end of said controlling member and one end of said compensating mem: ber, a movable contact, support means mounting said movable contact for conjoint movement by said connected ends, a contact actuating bracket carried by the connected ends of said controlling member and said compensating member, a heater forming a part of said controlling member, and leads adapted to supply current to said heater, said bracket being operative in response to the energizing of said heater and the expansion of said controlling member to move said movable contact support and effect a movement of said movable contact relative to said fixed contact.

3. In an electroathermally actuated relay, in combination, a base, a fixed contact mounted on said base, a relay movement, said relay movement comprising a frame, means on said base supporting said frame, an elongated electrically heated expansible controlling member having one end attached to said frame at a point remote from said supporting means on said base, an elongated compensating member having one end attached to said frame at a point adjacent said point of attachment of said controlling member thereto, said controlling member and said compensating member being disposed substantially in parallel relationship with each other, a movable contact, support means mounting said contact for movement relative to said fixed contact, means connecting the free ends of said controlling member and said compensating member, and a contact actuating element operatively connected to said controlling member and said compensating member and engaging said support means for effecting a movement of said movable contact relative to said fixed contact when said controlling member expands due to being electrically heated. I

4. In an electro-thermally actuated relay, in combination, a base, a fixed contact mounted on said base, spaced supporting lugs fixed to said base, a relay movement comprising a frame supported on said lugs, an elongated electrically heated expansible controlling member including a heater, and having one end attached to said frame at a point remote from said lugs, an elongated compensating member having one end attached to said frame at a point adjacent the point of attachment of said controlling member to said frame, said compensating member being disposed substantially parallel to said controlling member, means connecting the free ends of said controlling member and said compensating member, a movable contact, an actuating arm for said movable contact carried by said connected ends, and electric leads for said heater, whereby when a current is passed through said heater said controlling member expands due to being electrically heated and moves said actuating arm to effect a relative movement between said movable and fixed contacts.

5. The relay defined in claim 4, wherein said connecting means for the free ends of said controlling member and said compensating member comprises a substantially U-shaped bracket having its legs attached to said compensating member and the base thereof attached to said controlling member, and wherein said actuating arm is provided with adjustable means for varying the time of movement of said movable contact relative to said fixed contact.

6 In an electro-thermally actuated relay, in combination, a base, a fixed contact carried by said base, spaced supporting lugs fixed to said base, a relay movement assembly comprising a frame having one end attached to said lugs, an elongated electrically heated expansible controlling member having one end resiliently pivotally connected to said frame at a point remote from said lugs, an elongated compensating member also having one end resiliently pivotally connected to said frame at a point adjacent said pivotal point of attachment of said controlling member to said frame, said controlling member and said compensating member being disposed for operation in substantially parallel relationship, means joining the free ends of said controlling member and said compensating member, a movable contact, support means mounting said movable contact for movement relative to said fixed contact, a contact actuating arm carried by said joined free ends of said controlling and said compensating members, and electric leads for said heater, whereby when a current passes through said leads and energizes said heater said controlling member expands and said actuating arm moves said movable contact support to effect a relative movement between said movable and fixed contacts.

7. In an electro-thermally actuated relay, in combination, :a base, a fixed contact, means attaching said fixed contact to said base, a relay movement comprising an elongated rigid channel shaped frame supported on said base, an elongated electrically heated expansible controlling member including a heater, means mounting one end of said controlling member on said frame, an elongated channel shaped compensating member, means mounting one end of said compensating member on said frame with the opposite legs of said compensating member disposed on opposite sides along a portion of said frame, said controlling member and said compensating member being so mounted on said frame that they are disposed substantially in parallel operative relationship with each other, connecting means joining the free ends of said controlling and said compensating members, a movable contact, support means mounting said movable contact for movement relative to said fixed contact, and means carried by said connected ends and operative in response to the energization of said heater and the subsequent expansion of said controlling member for moving said movable contact relative to said fixed contact.

I 8. In an electro-thermally actuated relay, in combination, a base, a first contact carried by said base, a relay movement comprising a frame supported on said base, an elongated electrically heated expansible controlling member having one end pivotally attached to said frame, an elongated compensating member having one end pivotally attached to said frame at a point adjacent said pivotal attachment of said controlling member to said frame, means joining the free ends of said controlling member and said compensating member, the points of attachment to the frame and the point of junction of the free ends forming an elongated triangle of which the dis tance between the adjacent points of attachment to the frame is the shortest side, a second contact, support means mounting said second contact for movement relative to said first contact, and contact actuating means mounted on the joined ends of said controlling member and said compensating member and operative in response to the expansion of said controlling member due to being heated electrically for moving said second contact relative to said first contact.

9, In an electro-thermally actuated relay, in combination, a base, a first contact supported on said base, a relay movement comprising a substantially rigid frame attached to said base, an elongated electrically heated expansible controlling member, means pivotally attaching one end of said controlling member to said frame, an elongated compensating member, means pivotally attaching one end of said compensating member to said frame at a point adjacent said point of attachment of said end of said controlling member, means joining the free ends of said controlling member and said compensating member for conjoint lateral movement relative to the longitudinal taxes of said controlling and compensating members, a second contact, a support for said second contact, and means carried by said joined ends of said controlling member and said compensating member and operative in response to the expansion of said controlling member due to being electrically heated and the movement of said compensating member for effecting a relative movement between said first and second contacts.

10. The relay defined in claim 9, wherein said support for said second contact comprises a fiat spring and wherein said second contact is mounted on said spring, and wherein said means carried by the joined ends of said controlling member and said compensating member includes an arm, and an adjusting screw mounted in said arm for engaging said spring and for causing said spring to move when said controlling member expands.

11. In an electro-thermally actuated relay, in combination, a base, a first contact mounted on said base, a relay movement assembly, said assembly comprising a frame, an elongated electrically heatable eXpansi-ble controlling member mounted on said frame, an elongated compensating member also mounted on said frame at a point adjacent said point of attachment of said controlling rnernber to said frame, said controlling member and said compensating member being disposed in substantially parallel operative relationship with each other, means connecting one end of said controlling member and one end of said compensating member, a spring, a second contact carried by said spring, supports on said base holding said frame in operative position, and adjustable means attachcd to said connected ends of said controlling member and said compensating member to en gage said spring, said last named means being operable in response to the expansion of said controlling member due to heating for causing movement of said second contact relative to said first contact.

12. In an electro-thermally actuated relay of the type described, a base, a first contact, means mounting said first contact on said base, a relay movement assembly, said assembly comprising an elongated frame, means on said base attaching said frame to said base and positioning said assembly on said base in operative position, an elongated heatable expansible controlling member, means resiliently pivotally connecting one end of said controlling member to said frame, an elongated compensating member, means resiliently pivotally connecting one end of said compensating member to said frame at a point adjacent said point of attachment of said controlling member to said frame, connecting means joining the free ends of said controlling member and said compensating member, a spring attached to said frame, a second contact carried by said spring, and means carried by the connected ends of said controlling member and said compensating member to engage said spring for causing movement of said second contact relative to said first contact when said controlling member expands due to being electrically heated and said controlling member and said compensating member move towards said frame about their resilient pivots.

13. In an electro-therrnally actuated relay, a base, a first contact carried by said base, a relay movement assembly, said assembly comprising a frame, means on said base supporting said frame and mounting said assembly in operative position on said base, said assembly also including an electrically beatable expansible controlling member, means resiliently pivotally securing one end of said controlling member to said frame, an elongated compensating member having a generally U-shaped cross section, means resiliently pivotally connecting one end of said compensating member to said frame at a point adjacent said point of attachment of said end of said controlling member to said frame and with the spaced sides of said U of said compensating member channel located on opposite sides of said frame along a portion of the length thereof, connecting means joining the free ends of said controlling member and said compensating member, a flat spring, 'a second contact mounted on said spring, and means attached to the joined ends of said controlling member and said compensating member and bearing against said spring for causing relative movement between said second contact and said first contact when said controlling member expands due to being electrically heated.

14. An electro-thermally actuated relay movement adapted to be mounted on a base having a fixed contact, comprising a frame for supporting said movement on said base, an elongated electrically heated expansible controlling member having one end pivotally attached to said frame, an elongated compensating member also having one end pivotally attached to said frame at a point adjacent the point of attachment of said controlling member and disposed in spaced operative relationship with said controlling member, connecting means joining the free ends of said controlling member and of said compensating member, the points of attachment to the frame and the point of junction of the free ends forming an elongated triangle of which the distance between the adjacent points of attachment to the frame is the shortest side, a movable contact mounted for conjoint movement with said connected ends of said controlling and said spring positioned between said frame and said compensating member and operative to maintain said controlling member continuously under tension.

16. In an electro-thermally actuated relay, a base, a fixed contact mounted on said base, a relay movement including an elongated rigid frame, an electrically heatable expansible flexible controlling member mounted on said frame, an elongated compensating member also mounted on said frame and disposed in a substantially parallel relationship with said controlling member, connecting means joining one end of said controlling mem- 12 ber and one end of said compensating member, resilient means coacting with said compensating member to maintain said controlling member continuously under tension, a flat spring attached to said frame, a second contact carried by said flat spring, projecting lugs on said base connecting said frame to said base, adjustable means attached to said joined ends of said controlling and said compensating members and bearing against said spring for causing movement of said second contact relative to said fixed contact when said controlling member expands due to being electrically heated.

17. The relay movement defined in claim 14, wherein said controlling member is flexible, and resilient means coacting with said compensating member for maintaining said controlling member continuously under tension.

18. The invention defined in claim 8, wherein said contact actuating means includes an arm attached to said joined ends of said controlling member and said compensating member, an adjusting screw threadably supported in said arm, and a spring attached to said frame supporting said movable contact positioned for engagement by said adjusting screw.

19. In an electro-thermally actuated relay, in combination, a base, a first contact mounted on said base, a second contact coacting with said fixed contact, a relay movement comprising a frame, an elongated electrically heatable expansible controlling member having one end pivotally attached to said frame, an elongated compensating member also having one end pivotally attached to said frame at a point adjacent the point of attachment of said controlling member, means joining the free ends of said controlling member and said compensating member, the points of attachment to the frame and the point of junction of the free ends forming an elongated triangle of which the distance between the adjacent points of attachment to the frame is the shortest side, means connecting said frame to said base, and means on said connected ends of said controlling member and said compensating member for effecting relative movement between said [first contact and said second contact when said controlling member expands due to being heated.

20. The invention defined in claim 19, wherein said controlling member supported by said frame and connected at one end to said compensating member is flexible, and wherein said movement includes a spring coacting with said compensating member for maintaining said controlling member continuously under tension.

21. In an electro-thermally actuated relay, in combination, a base, a first contact carried by said base, spaced supporting lugs fixed to said base, a relay movement comprising an elongated frame having one end attached to said lugs whereby to maintain said movement in operative arrangement on said base, an elongated flexible electrically heatable expansible controlling member having one end resiliently pivotally connected to said frame, at

a point remote from said base, an elongated compensating member having one end resiliently pivotally connected to said frame at a point adjacent the point of attachment of said controlling member to said frame, said controlling member and said compensating member being disposed in substantially parallel spaced operative relationship, means connecting the free ends of said controlling and said compensating members, a second contact, a flexible element supporting said second contact, means on said connected ends of said controlling member and said compensating member and acting on said flexible element for causing relative movement between said first contact and said second contact when said controlling member expands due to being electrically heated, and a spring coacting with said compensating member for maintaining said controlling member continuously under tension.

22. The invention defined in claim 8 wherein said means joining the free ends of said controlling member and said compensating member comprises a U-shaped bracket having its legs attached to said end of said compensating member and its base secured to said end of said controlling member, and wherein said contact actuating means comprises an adjustable contact actuating screw, resilient means attached to said joined ends of said controlling member and said compensating member for restraining said adjusting screw from turning as a result of vibration or shock and a flexible support for said second contact, said screw being adapted to bear against said flexible support to move said movable contact when said controlling member expands.

23. In an electro-thermally actuated relay, in combination, a base, a first contact mounted on said base, a second contact .coacting with said first contact, a flexible element supporting said second contact, a relay movement comprising a frame, an elongated electrically heatable expansible controlling member mounted on said frame, an elongated compensating member also mounted on said frame and substantially parallel to and laterally spaced from said controlling member, connecting means joining the free ends of said controlling and said compensating members, a spring positioned between said frame and said compensating member for maintaining said controlling member continuously under tension, means on said base joining said frame to said base, and adjustable means operative in response to the movement of said compensating member and the expansion of said controlling member due to being heated electrically for effecting a relative movement between said first contact and said second contact.

24. The relay defined in claim 1, wherein said support means for said second contact comprises a flexible element, a third contact carried by said flexible element and spaced from said second contact, a fourth contact coacting with said third contact, and support means for said fourth contact, and wherein said contact operating means carried by said connected ends of said controlling member and said compensating member is operable to effect relative operational movement between said third and fourth contacts when said controlling member expands, and to cause relative operational movement between said first and second contacts upon further heating and expanding of said con-trolling member.

25. The invention defined in claim 24, wherein said contact operating means includes an adjusting device for adjusting the position of said fourth contact relative to said third contact, said device comprising an arm carried by said joined ends of said controlling member and said compensating member, and a threadably supported adjusting screw in said arm.

26. The invention defined in claim 24, wherein said controlling member is flexible, and wherein said relay movement includes a spring coacting with said compensating member for continuously maintaining said controlling member taut and under tension.

27. In an electro-thermally actuated relay, in combination, a base, a first contact carried by said base, a relay movement comprising an elongated frame supported on said base, an elongated electrically heatable expansible controlling member carried by said frame, an elongated compensating member also carried by said frame and disposed in laterally spaced substantially parallel operative relationship with said controlling member, connecting means joining the free ends of said controlling member and said compensating member, a second contact, and means operative in response to the conjoint lateral movement of said connected free ends of said compensating and controlling members relative to their longitudinal axes, when said controlling member expands due to being heated electrically, for eifecting a relative movement between said second contact and said first contact.

28. In an electro-thermally actuated relay, in combination, a base, a first contact carried by said base, a relay movement comprising an elongated rigid frame carried by said base, an elongated electrically heatable expansible controlling member, means attaching one end of said controlling member to said frame at a point remote from said base, an elongated compensating member, means attaching one end of said compensating member to said frame at apoint adjacent said point of attachment of said end of said controlling member, said controlling member and said compensating member being disposed in laterally spaced substantially parallel operative relationship with each other, means connecting the free ends of said controlling member and said compensating member, a second contact, and means operative inresponse to the expansion of said controlling member due to being heated electrically and the conjoint movement of said compensating member for effecting a movement of said second contact relative to said first contact.

29. The invention defined in claim 28 wherein said controlling member which is supported by said frame and said connection to said compensating member is flexible and wherein said relay movement includes a spring coacting with said compensating member for continuously maintaining said controlling member under tension and thereby preventing it from buckling or collapse.

30. In an electro-thermally actuated relay, in combination, a base, a first contact mounted on said base, a relay movement comprising a frame supported on said base, an elongated electrically heated longitudinally exp ansible controlling member, means mounting one end of said controlling member on said frame, an elongated compensating member, means mounting one end of said compensating member on said frame and disposing said compensating member in spaced relationship with said controlling member, means joining the free ends of said controlling member and said compensating member, a second contact carried by the joined ends of said controlling member and said compensating member, and means for expanding said controlling member whereby said second contact in response to the conjoint lateral movement of said joined ends of said controlling member and said compensating member relative to their axes, is moved relative to said first contact.

31. In an electro-thermally actuated relay, a base, a first contact mounted on said base, a relay movement comprising a substantially rigid frame mounted on said base, an elongated electrically heated expansible actuating member, means pivotally mounting one end of said actuating member on said frame, an elongated compensating member, means pivotally mounting one end of said compensating member on said frame at a point ad acent the point of support of said actuating member thereon, means joining the free ends of said actuating member and said compensating member for conjoint lateral movement relative to the longitudinal axes of said actuating and said compensating members, a second contact, a flexible support for said second contact, and means carried by the joined ends of said actuating member and said compensating member and operative in response to the expansion of said actuating member due to being electrically heated for effecting relative movement between said first and second contacts, said flexible support being operative after engagement of said contacts and in response to additional expansion of said actuating member to effect a rolling action between said contacts, whereby to insure and maintain a good contact therebetween.

32. The relay defined in claim 31, wherein said actuating member comprises a rigid shell, and an electrical heating element enclosed in said shell.

33. The relay defined in claim 31, including a third contact carried by said flexible support, a fourth contact coacting with said third contact, and wherein said movement of said compensating member in response to the expansion of said actuating member is operable to effect a relative operational movement between said third and fourth contacts prior to the relative operational movement eifected between said first and second contacts in response References Cited in the file of this patent to the expansion of said actuating member. UNITED STATES PATENTS i 34. The invention set forth in claim 23 including a third contact carried by said flexible element supporting 1111789 Freas Sept 1914 2,664,483 Broekhuysen Dec. 29, 1953 i said second contact, a fourth contact co-actmg with said 5 d thir d h 2,700,084 Broekhuysen Jan.18, 1955 l 0 1r contact, and wherem szud d an fourt contacts 2,782,285 Canflin Feb 19, 1957 l are moved relatively to each other in timed relation to the relative movement effected between said first and sec- FOREIGN PATENTS 0nd contacts in response to the expansion of said con- 159,478 Great Britain Aug.25,192Z trolling member. 688,264 Great Britain Mar. 4, 1953 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,948,788 August 9, 196

William C. Broekhuysen It is herebjr certified that error appears in the-printed specificatio of the above numbered patent requiring correction and that the said Letter Patent should read as corrected below.

Column 8, lines 29 30, and 31, strike out "and the conjoint lateral movement of the connected ends of said controlling member and said compensating member" and insert the same after controlling member"' in line 32 same column 8 Signed and sealed this llth day of April 1961.

(SEAL) Attest:

ERNEST W. SWIDER ARTHUR W. CROCKER Attesting Officer Acting Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,948,788 August 9,, 196

William Ce Broekhuysen It is herebjr certified that error appears in the-printed specificatio:

of the above numbered patent requiring correction and that the said Letter; Patent should read as corrected below.

Column 8, lines 29, 30 and 31 strike out "and the conjoint lateral movement of the connected ends of said controlling member and said compensating member" and insert the same after controlling member"- in line 32 same column 8 Signed and sealed this llth day of April 1961.

(SEAL) Attest:

ERNEST W. SWIDER ARTHUR W. CROCKER Attesting Officer Acting Commissioner of Patents 

